A thermosetting material such as thermosetting resin starts a curing reaction on heating, the curing reaction having a velocity that increases with a rise in temperature of the thermosetting material. Further, since this curing reaction is normally an exothermic reaction, the thermosetting material generates heat (self heat generation) as the curing reaction progresses.
When a thermosetting material is thermally cured to be molded, the temperature of the thermosetting material is increased as it is heated by external means and also as a result of self heat generation. This temperature increases further accelerates the curing reaction, with the result of such excessive heating causing thermal runaway, that is, causing the curing reaction to progress drastically.
FIG. 40 is a graph for illustrating thermal runaway caused by excessive heating in a thermosetting material. As illustrated in FIG. 40, excessive heating causes the velocity of a curing reaction in a thermosetting material to increase drastically, which in turn causes thermal runaway in the thermosetting material. Thermal runaway may problematically result in a molded article having unevenness in physical property, deformation, residual stress, and/or decrease in strength.
In relation to such a problem, Patent Literature 1 discloses a technique of (i) predicting, on the basis of (a) a formula for calculating the velocity of a curing reaction occurring in a thermosetting material, (b) an equation of heat balance in an autoclave, (c) a measured value of the atmosphere temperature in the autoclave, and (d) a measured value of the temperature of the thermosetting material, a temperature change to occur in the thermosetting material after the current time instant and thus (ii) controlling the atmosphere temperature.